/*
 * Copyright 2002-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.web.servlet.view.xslt;

import org.springframework.lang.Nullable;
import org.springframework.web.servlet.view.AbstractUrlBasedView;
import org.springframework.web.servlet.view.UrlBasedViewResolver;

import javax.xml.transform.ErrorListener;
import javax.xml.transform.URIResolver;
import java.util.Properties;

/**
 * {@link org.springframework.web.servlet.ViewResolver} implementation that
 * resolves instances of {@link XsltView} by translating the supplied view name
 * into the URL of the XSLT stylesheet.
 *
 * @author Rob Harrop
 * @author Juergen Hoeller
 * @since 2.0
 */
public class XsltViewResolver extends UrlBasedViewResolver {

    @Nullable
    private String sourceKey;

    @Nullable
    private URIResolver uriResolver;

    @Nullable
    private ErrorListener errorListener;

    private boolean indent = true;

    @Nullable
    private Properties outputProperties;

    private boolean cacheTemplates = true;


    public XsltViewResolver() {
        setViewClass(requiredViewClass());
    }


    @Override
    protected Class<?> requiredViewClass() {
        return XsltView.class;
    }

    /**
     * Set the name of the model attribute that represents the XSLT Source.
     * If not specified, the model map will be searched for a matching value type.
     * <p>The following source types are supported out of the box:
     * {@link javax.xml.transform.Source}, {@link org.w3c.dom.Document},
     * {@link org.w3c.dom.Node}, {@link java.io.Reader}, {@link java.io.InputStream}
     * and {@link org.springframework.core.io.Resource}.
     */
    public void setSourceKey(String sourceKey) {
        this.sourceKey = sourceKey;
    }

    /**
     * Set the URIResolver used in the transform.
     * <p>The URIResolver handles calls to the XSLT {@code document()} function.
     */
    public void setUriResolver(URIResolver uriResolver) {
        this.uriResolver = uriResolver;
    }

    /**
     * Set an implementation of the {@link javax.xml.transform.ErrorListener}
     * interface for custom handling of transformation errors and warnings.
     * <p>If not set, a default
     * {@link org.springframework.util.xml.SimpleTransformErrorListener} is
     * used that simply logs warnings using the logger instance of the view class,
     * and rethrows errors to discontinue the XML transformation.
     *
     * @see org.springframework.util.xml.SimpleTransformErrorListener
     */
    public void setErrorListener(ErrorListener errorListener) {
        this.errorListener = errorListener;
    }

    /**
     * Set whether the XSLT transformer may add additional whitespace when
     * outputting the result tree.
     * <p>Default is {@code true} (on); set this to {@code false} (off)
     * to not specify an "indent" key, leaving the choice up to the stylesheet.
     *
     * @see javax.xml.transform.OutputKeys#INDENT
     */
    public void setIndent(boolean indent) {
        this.indent = indent;
    }

    /**
     * Set arbitrary transformer output properties to be applied to the stylesheet.
     * <p>Any values specified here will override defaults that this view sets
     * programmatically.
     *
     * @see javax.xml.transform.Transformer#setOutputProperty
     */
    public void setOutputProperties(Properties outputProperties) {
        this.outputProperties = outputProperties;
    }

    /**
     * Turn on/off the caching of the XSLT templates.
     * <p>The default value is "true". Only set this to "false" in development,
     * where caching does not seriously impact performance.
     */
    public void setCacheTemplates(boolean cacheTemplates) {
        this.cacheTemplates = cacheTemplates;
    }


    @Override
    protected AbstractUrlBasedView buildView(String viewName) throws Exception {
        XsltView view = (XsltView) super.buildView(viewName);
        if (this.sourceKey != null) {
            view.setSourceKey(this.sourceKey);
        }
        if (this.uriResolver != null) {
            view.setUriResolver(this.uriResolver);
        }
        if (this.errorListener != null) {
            view.setErrorListener(this.errorListener);
        }
        view.setIndent(this.indent);
        if (this.outputProperties != null) {
            view.setOutputProperties(this.outputProperties);
        }
        view.setCacheTemplates(this.cacheTemplates);
        return view;
    }

}
